Here's how Hemingway biographer A.E. Hotchner recorded the preparation of Hemingway's Daiquiris that they drank at El Foridita in 1948:

"A Papa Doble was compounded of two and a half jiggers of Bacardi White Label Rum, the juice of two limes and half a grapefruit and six drops of maraschino...placed in an electric mixer over shaved ice, whirled vigorously and served foaming in large goblets."

Hemingway held the record for drinking 16 in one night. That is 60 ounces of rum -- 2 and 1/3 standard size (750ml) bottles worth. He liked them slushie, because they slid down more easily -- and he liked them without sugar, because that much sugar would kill a horse. _________________David J. Montgomery
Professor Cocktail

Hemingway had a hereditary disease called Hemochromatosis, which can cause diabetes (amongst a litany of other maladies). Ernest's father, Clarence, had the disease, as well as diabetes, and it was likely one of the reasons he killed himself. Papa wanted to avoid that fate, so he ordered his drinks without sugar.